The present disclosure relates to a liquid-crystal lens, display apparatus and electronic equipment.
If a voltage is applied between electrodes, which are opposed to each other to sandwich a liquid-crystal layer, in order to control an electric-field distribution in the liquid-crystal layer, liquid-crystal molecules included in the liquid-crystal layer are oriented in accordance with the electric-field distribution. The liquid-crystal molecules have refractive-index anisotropy. Thus, when the orientation state changes, the refractive index for light incident to the liquid-crystal layer also changes as well. Utilizing such a phenomenon, the electric-field distribution applied to the liquid-crystal layer is controlled by controlling the voltage applied between the electrodes in order to produce a refractive-index distribution exhibiting a lens effect. Thus, by controlling the voltage applied between the electrodes, the electrodes and the liquid-crystal layer can be used as a liquid-crystal lens.
For example, Japanese Patent Laid-open No. 2009-53345 discloses a three-dimensional display apparatus having a liquid-crystal lens making use of two lower electrodes for every lens. In order to implement a good liquid-crystal lens, the electric-field distribution applied to the liquid crystal needs to be controlled with a high degree of precision. For this reason, Japanese Patent Laid-open No. 2011-150344 and Japanese Patent Laid-open No. 2011-164527 disclose a liquid-crystal lens in which a number of lower electrodes are provided for every lens by being separated from each other by an equal pitch.